Are you cool? Before you answer that, give some thought to what it means to be cool. Does it depend upon the clothes you wear, the people you hang out with, the music you listen to or the sports you play?

Some people might think that those are the things that determine whether you're cool or not. But guess what? You don't have to live by others' definitions of what's cool. You can decide what's cool for yourself.

You know what we think is cool? Kids who love to WONDER! That's you! So if you're visiting Wonderopolis today, you're cool in our book.

Today, we want to take a look at how cool people are…temperature-wise. You probably already know that humans are mammals and that means they're warm-blooded. Warm-blooded animals are those animals whose temperatures are regulated and kept fairly constant by processes inside their bodies.

Cold-blooded animals, on the other hand, are animals whose temperature depends upon the environment around them. They don't necessarily have blood that's actually cold. It just varies based upon the temperature of the environment around them. Some examples of cold-blooded creatures include most reptiles, fish, amphibians and insects.

The human body works hard to maintain a relatively constant body temperature of 98.6° F. If you've ever been outside when it's almost 100° F, you know that's hot. So if you think you're cool, you're always hot, too…at least on the inside!

Unlike cold-blooded animals that can rely on sunlight to regulate their body temperature, humans and other warm-blooded animals must eat more food to create their own body heat to maintain their optimum temperature. That's why cold-blooded animals can survive on much less food and in harsh environments that warm-blooded animals couldn't stand.

Varying too far from 98.6° F can be very dangerous for humans. If your internal temperature drops too much, your body's organs cannot work properly. Likewise, if your temperature gets too hot, you begin to feel very sick.

Have you ever had a fever? That's what it's called when your internal temperature exceeds the normal level of 98.6° F. If you've ever had a fever, you know how awful it feels. That's why you have to take medicine to help return your body temperature to normal as soon as possible.

If you think about it, it's amazing how your body maintains a normal internal temperature all the time…no matter whether you're shivering from throwing snowballs or sweating from running on the beach! Your body's nervous system orchestrates the work of your muscles, blood vessels and sweat glands to keep the inside of your body a toasty 98.6° F at all times.

As your body burns food for fuel, which it does almost constantly, heat is produced. This heat keeps your body warm. If you lower the temperature of the blood by, for example, taking a cold shower or going outside without a jacket during the winter, your body responds by burning more fuel to produce more heat.

If your body cools off too quickly, you may begin to shiver. This is another way your body heats up again. As your muscles contract as you shiver, more fuel is burned and heat is produced to warm your body.

If your blood gets too warm, your body also has ways of cooling you off. Your skin is usually always much cooler than your internal temperature. When you get too hot, your body may push more of your blood closer to your skin, where it is cooled before it is returned to the rest of your body.

Your skin also has tons of sweat glands. These glands help produce sweat, which helps transfer heat and cool you off as it evaporates from your skin. Even when it's not hot outside, your body sweats enough each day to get rid of about a quarter of the heat produced by your body! Now that's cool!

Wonder What's Next?

Tomorrow’s Wonder of the Day may have you saying, “Hair today, gone tomorrow!”